Electrophysiological techniques are being used to elucidate the role of branchiostegite hair pit receptors in the behavior of the crayfish, Procambarus Clarkii. An extensive analysis of the electrical properties of the individual sensory neurons is now being completed, and the pathways taken by axons from these cells within the central nervous system is now being mapped. Overall behavioral responses to stimulation of the hair pit receptors will be examined, and these studies will then be supplemented by electrophysiological techniques to determine the target neurons of the sensory receptors and the motor output pathways involved in the behavior. We are especially interested in the way in which the crayfish brain can process information from a well-defined sensory field, including a knowledge about the ways in which input from other sense organs can modify the effectiveness of the pathway under observation.